County Executive Ed Mangano is calling for a downsized Nassau Coliseum, and is seeking a private company to finance the renovations while operating the venue.

SMG, a property management company, currently operates the Coliseum, with a lease that expires in 2015. The company manages more than 60 arenas and stadiums across the world, including the Superdome in New Orleans and Soldier Field in Chicago, as well venues in the United Kingdom and Poland.

Asked how operating responsibilities would be delegated between SMG and the developer, Nevin said that was “to be determined.” SMG did not respond to a request for comment.

Mangano indicated that Ratner’s role as an advisor has been fulfilled. A spokesman for Ratner’s development company, Forest City Ratner, did not say whether the company would bid on the Coliseum project. But in a statement that he attributed to Ratner, the spokesman said, “Based on our review of the arena and the marketplace, we believe that the Nassau Veterans Memorial Coliseum can be a viable entertainment venue. The arena sits in one of the most vital centers of the metropolitan region, within easy access to hundreds of thousands of fans. Developed properly, we think the arena will be a great success.”

Renaissance Downtowns will continue its role as “master developer” of the Coliseum site, and will work directly with the chosen developer. The company did not respond to repeated requests for comment.

In December, the New York State Regional Development Council Initiative awarded $500,000 to the county to redevelop the Coliseum. At the time, Brandon Palanker, vice president of marketing and public affairs for Renaissance Downtowns, told the Herald that a plan would be made “over the coming weeks” as to how to best use the money.

But Palanker said that an entertainment and sports complex, and a facility that would house professionals in science and medicine, would be ideal, and that the company had already begun making inquires to local organizations and universities to gauge interests in building at the site.